RU2534659C2 - Axial journal bearing - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: invention relates to the thrust journal bearings, which one work surface is out of siliconised graphite (or other antifriction material with similar characteristics), and can be used in assemblies of the electric machines and hydraulic machines with large-size thrust bearings (diameter up to 900mm), mainly in motors driving the main circulating pump units of the reactor plants, for example at NPS. The feature of the mentioned axial bearing is that the support disc if made with alternating supporting shoulders and grooves from the side looking towards a set of sectors out of antifriction material. On outside and internal diameters of the supporting disc the seating surfaces are made, the outside and internal rings are installed in them and secure the sectors via the resilient elements. The sectors locking against rotation relatively to the supporting disc is ensured by the intermediate planks installation between the sectors, they are locked by the plank axle in holes of the supporting disc. The sectors are made with steps for outside and internal rings, the sector top part has radial roundings, and bottom part has grooves ensuring mutual securing. Lead-in edge of the sector has shape similar to parabolical shape. Cooling and lubrication are performed via the alternating channels created by the planks, sectors, outside and internal rings.

EFFECT: decreasing of possibility to damage the antifrictional components out of siliconised graphite due to bend stresses and thermal deformations due to non-uniformity of heat removal from the contact zone when solid gusset is used; improvement of the cooling and lubricating water circulation on crown surface of the axial journal bearing; improvement of feasibility of the gusset manufacturing and assurance of its reparability; reliability improvement; fire risk decreasing; rotation prevention of the set of sectors over the supporting disc.

3 cl, 8 dwg

Description

The invention relates to thrust sliding bearings, in which at least one of the working surfaces is made of silicon graphite (or other antifriction materials with similar characteristics). The main area of its application is the corresponding structural units of electric machines and hydraulic machines with thrust bearings of large dimensions (up to 900 mm in diameter), mainly electric motors that drive the main circulation pump units (GTsNA) and the main circulation pump units of water-cooled reactor plants, for example, at nuclear power plants ( NUCLEAR POWER STATION). Siliconized graphite (as an antifriction bearing material) is characterized by temperature resistance (at least up to 300 ° C) and allows the use of water instead of oil as a cutting fluid. Such a solution is used in the radial and thrust bearings of the vane pumps that make up the GTsNA.

However, due to the fragility, lower coefficient of linear expansion than that of metal, the complexity of the process of manufacturing a lining in the form of a single part with a maximum overall size of up to 900 mm and ensuring uniform and efficient heat removal from the friction zone when using a single lining, it is impossible to obtain plates for thrust bearings large-diameter slip using siliconized graphite lubricated and cooled with water as an antifriction material.

Known axial bearings for powerful steam turbines (Serezhkina L.P., Zaretsky E.I. Axial bearings of powerful steam turbines. Mechanical Engineering, 1988, pp. 39 ... 41) mounted on a shaft with a ridge moving between two sets of blocks with the Kingsbury leveling lever system, which uses oil as a cooling and lubricating fluid.

A disadvantage of the known plain bearings, using oil as a cooling and lubricating fluid, is the increased fire hazard of the equipment of nuclear power plants, including the main circulation pumps operating in a maintenance-free room. To ensure fire safety, a transition to a non-combustible lubricating-cooling liquid-water is required. The transition to water will require structural changes, in particular the installation on the crest of a lining with antifriction material that is operable during cooling and lubrication with water.

Known thrust bearing (US Pat. RU No. 2242645, F16C 17/04, published July 15, 2003), comprising a housing and a flange mounted on the shaft with a flange, on the supporting surface of which a thrust disk is installed, and a node is located between the housing and the disk with self-aligning pads equipped with anti-friction linings in contact with the disk on their supporting surfaces, includes a clamping ring with windows (separator) fixed on the working surface of the assembly with self-aligning pads and anti-friction linings (separator) akladok made as inserts freely arranged in the windows of the pressure ring, wherein the working surface of antifriction bushings protrudes above the end surface of the tightening ring. The thrust disc is made in the form of a continuous antifriction ring. Antifriction liners are made in a cross-section of a stepped form, while the steps keep the liners from falling out of the windows of the clamping ring.

A disadvantage of the known thrust sliding bearing is the use of a disk in the form of a continuous antifriction ring made in the form of a monoblock on the flange (ridge), which is impossible in the case of creating a large size sliding bearing (up to 900 mm in diameter). In addition, load balancing in the contact zone due to the axial spring ring with liners of antifriction material is not possible in the axial sliding bearing at high specific loads.

Known persistent bearing sliding unit (US Pat. RU No. 1745004, F16C 17/04, publ. 28.02. 1994), comprising a housing and a shaft with a flange, on the supporting surface of which is installed a disk with ring protrusions, and between the case and the disk self-aligning pads with contact with the disk on their working surfaces.

This is a well-known technical solution that provides the possibility of operation of a thrust sliding bearing at high specific loads using antifriction linings made of siliconized graphite, when water is used as a cutting fluid, has the disadvantage of the absence of leveling of specific loads on self-aligning sectors and the possibility of erosive damage from hydrodynamic effects coolant flow during continuous operation of an axial plain bearing shih dimensions.

The problem solved by the invention is to form a patch over the contact surface of the shaft ridge with a large axial sliding bearing mounted, with a lever leveling Kingbury system that works using siliconized graphite (or other materials with similar characteristics) as antifriction material under cooling and bearing lubrication water corresponding to the operation of the MCPA at nuclear power plants.

When implementing the invention, the following technical results can be obtained:

- reducing the possibility of damage to antifriction elements of siliconized graphite from bending stresses and thermal deformations due to uneven heat removal from the contact zone when using a solid form of the lining;

- improving the circulation of cooling and lubricating water on the surface of the ridge of an axial plain bearing;

- improving the manufacturability of the lining of the crest of the axial plain bearing of large dimensions;

- ensuring maintainability of the lining of the crest of the axial plain bearing of large dimensions;

- increased reliability;

- reduction of fire hazard;

- preventing the rotation of the set of sectors on the support disk.

As a solution to the problem, which allows achieving an effect with the indicated characteristics, an axial plain bearing is proposed, comprising a housing and a shaft with a flange, on the supporting surface of which there is a disk with ring protrusions, and between the case and the disk there are self-aligning blocks with contact with the disk along their working surfaces, self-aligning pads equipped with anti-friction linings, two annular protrusions are made on the supporting surface of the disk, and antifriction segments are installed on its working surface, according to the invention, it is proposed that the support disk be made with alternating support belts and grooves from the side facing the set of sectors, along the outer and inner diameters of the support disk, to make seating surfaces in which the outer and inner rings are mounted, securing sectors from antifriction material through elastic elements, fixing sectors from rotation relative to the support disk, perform the installation of intermediate strips between sectors that are fixed by the axis of the strap in the holes of the support disk,

sectors of antifriction material to perform with steps for the outer and inner rings, in the upper part of the sector to make radius curves, in the lower part - grooves that provide mutual axial fixation, the edge of the entry sector to make a shape close to parabolic,

while cooling and lubrication is carried out through alternating channels formed by strips, sectors, outer and inner rings.

It is advisable to fasten the lining to the ridge in the interval between the support belts with bolts or screws with the possibility of locking from self-loosening.

Preferably, the sectors are made of siliconized graphite or silicon carbide.

Technical results are achieved as follows.

To reduce the possibility of damage and transmission during operation of bending deformations and thermal deformations from the ridge to sectors of siliconized graphite (or other material with similar characteristics), the support disk contains support belts on the surface facing the ridge in an area close to the inner equilibrium center and the outer surface of the sectors of siliconized graphite.

To prevent rotation of the set of sectors along the support disk during operation, each sector is locked by the lateral surface of the (intermediate) strip installed between the sectors. The straps are fixed relative to the support disk by the axis of the strap installed in the hole of the support disk, in the particular case, the sectors can be prevented from rotating by groups, locking is done by the straps having an axis of attachment and installed at the beginning and end of the group of sectors. The slats together with the (profiled) sectors of siliconized graphite (or other material with similar characteristics) and the external and internal retaining rings form channels that provide, during operation, improved circulation of cooling and lubricating water on the contact surface of the axial plain bearing flange.

The use of a set of sectors of siliconized graphite (or other antifriction material with similar characteristics) provides an improvement in the manufacturability of the manufacture of a large-sized axial plain bearing crest.

The possibility of replacing individual sectors of the lining during manufacturing and operation ensures maintainability of the lining of the large axial plain bearing crest.

To reduce the fire hazard of the equipment of nuclear power plants, including the main circulation pumps operating in a maintenance-free room, use non-combustible cooling and lubricating fluid - water, and install on the crest of the lining with antifriction material that is operable during cooling and lubrication with water.

The claimed invention, in a particular embodiment, is illustrated by the drawings:

FIG. 1 - axial plain bearing;

FIG. 2 - a slip of an axial plain bearing - general view;

FIG. 3 - lining channels - view B (figure 2);

FIG. 4 - overlay - section aa (figure 2);

FIG. 5 - lining sector - general view;

FIG. 6 - lining sector - side view (figure 5);

Fig.7 - strip lining - General view;

FIG. 8 - strip lining - view G (Fig.7).

A large-sized axial plain bearing is made in a housing (not shown), mounted on a shaft ridge moving between two sets of blocks, with a Kingbury leveling linkage system located between the housing and the support disk 1, ridge 26, and plates 27 mounted on it (Fig. 1 ) The pad 27 (figure 2) includes a support disk 1 (figure 4), made in the form of a ring with a seating surface on the inner diameter.

On the side facing the set of sectors (Fig. 4), the support disk 1 is made with a surface in the form of alternating grooves 2 and support belts 3, creating the necessary support conditions from the strength conditions for silicon graphite, while ensuring a minimum surface area for mutual contact.

From the side facing the ridge 26, the support disk 1 is made with two support belts 4 (Fig. 4) located in the zone close to the center of equilibrium of the internal and external surfaces of the silicon graphite sectors to reduce the possibility of damage and transmission during operation of bending deformations and thermal deformations from the crest to the sectors.

On the inner and outer diameters of the support disk 1 (Fig. 4), from the sectors, annular grooves (steps) 5 and 6 are coaxial to the seating surface of the support disk for aligning the outer 7 and inner 8 rings, respectively. On the upper abutment surface of the abutment disk 1, a set of sectors 9 (Fig. 2,4) is made of siliconized graphite made in the form of a sector and its working contact surface. The use of a set of sectors of siliconized graphite provides an improvement in the manufacturability of the manufacture of a large-size axial plain bearing crest, increasing reliability and maintainability during operation.

To prevent the occurrence of hydrodynamic disturbances, the edge 10 of the input (figure 2, 5) sectors 9 is made deviating from the radial direction in the direction of rotation on a larger diameter of the sectors. To ensure a smooth change in the direction of flow of cooling and lubricating water in the grooves at the inlet and outlet between sectors from the circumferential direction to the radial and, conversely, the edge 10 of the entry sector has a shape close to parabolic (Fig. 3), and along the external and internal contours corresponding radius curves 11, 12, and 13, 14 (FIG. 5). Using water as a cooling and lubricating fluid, fire safety is ensured.

The sectors 9 are fixed during rotation operation relative to the support disk 1 by using the lateral surface of the (intermediate) strips 15 (Figs. 4, 7) installed by the axis 16 into the holes 17 of the support disk 1, by the stops 18 (Fig. 8) in the grooves 19 ( 6) sectors, providing mutual axial fixation.

The sectors 9 are fixed relative to the supporting disk 1 (Fig. 4) by the outer 7 and inner 8 rings and elastic elements 20 and 21 (Fig. 4).

An additional fixation of the sectors 9 from rotation relative to the support disk 1 is performed by locking the sectors with a pin against the outer 7 and inner 8 rings.

The fixing of the external 7 and internal 8 rings to the disk is carried out, in the particular case, by bolts 22 and screws 23 (Fig. 4), lock washers 24 and 25 (Fig. 4).

The lining 27 of the axial plain bearing to the ridge 26 is mounted in the interval between the support belts 4 (in the particular case, bolts or screws that are locked against self-loosening).

The assembly of the lining is carried out by installing the strips 15 on the support disk 1, followed by the installation of sectors 9, elastic elements 20, 21, and the fixing of the outer 7 and inner 8 rings with their fastening to the support disk.

Claims (3)

1. An axial plain bearing, comprising a housing and a shaft with a flange, on the supporting surface of which a disk with annular protrusions is mounted, and between the housing and the disk are self-aligning blocks with contact with the disk along their working surfaces, self-aligning blocks are equipped with anti-friction linings, on the supporting surface of the disk two annular protrusions are made, and antifriction segments are installed on its working surface, characterized in that the support disk is made with alternating support belts and grooves with sides On the outside of the set of sectors, the outer surfaces and the inner diameters of the supporting disk are provided with seating surfaces in which the external and internal rings are mounted, securing the sectors of antifriction material through elastic elements, the sectors were fixed from rotation relative to the supporting disk by installing intermediate strips between the sectors, which fixed by the axis of the strap in the holes of the support disk, sectors of antifriction material are made with steps for the outer and inner rings, in the upper part sectors, radiuses were made, grooves in the lower part providing mutual axial fixation, the edge of the entry sector is made in a shape close to parabolic, while cooling and lubrication are carried out through alternating channels formed by planks, sectors, outer and inner rings. 2. The axial plain bearing according to claim 1, characterized in that the lining is fixed to the ridge in the interval between the support belts with bolts or screws with the possibility of locking from self-loosening. 3. The axial plain bearing according to claim 1, characterized in that the sectors are made of siliconized graphite or silicon carbide.

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